[13][14][15] Arihant holds the distinction of being the first ballistic missile submarine to have been built by a country other than one of the five permanent members of the United Nations Security Council.

The records of Nixon-Kissinger communications show no contingency nor any plan under which Enterprise would enter Indian or Pakistani waters, or otherwise intervene in the conflict but it is well known that the duo viewed Pakistan as a strong ally in that region and were silent on Bangladesh genocide committed by Pakistani military.

[20] The event demonstrated the significance of nuclear weapons and ballistic missile submarines to then Prime Minister Indira Gandhi.

[22] The Indian Navy's Advanced Technology Vessel project to design and construct a nuclear submarine took shape in the 1990s.

[24] The initial intent of the project was to design nuclear-powered fast attack submarines, though following nuclear tests conducted by India in 1998 at Pokhran Test Range and the Indian pledge of no first use, the project was re-aligned towards the design of a ballistic missile submarine in order to complete India's nuclear triad.

[49] Facilities for loading and replacing the fuel cores of the naval reactors in berthed submarines were also established.

[21] The prototype 83 MW light water reactor that was installed at Kalpakkam by BARC is codenamed S1 and is used to train nuclear submariners.

[4] In 2007, then finance minister P. Chidambaram, who was a member of the political committee which monitors the ATV programme, questioned the huge amount of money being spent on submarines with just 4 missile launch tubes.

Hence, the ATV project team tweaked the Arihant design by adding a 10-metre-long section for four more K-4 SLBMs to be integrated into the boat codenamed S4.

After it became evident that the larger S5 class of SSBNs will take more time to develop, an additional unit, codenamed S4*, was sanctioned in 2012 to ensure that the production line doesn't go idle.

[54] The lead vessel underwent a long and extensive process of testing after its launch in July 2009.